Driveway Surfacing and the 2008 Drainage Rules: A Practical Summary
The regulations on impermeable driveways are widely misunderstood. Here is exactly what is required and the practical options for compliance.
In October 2008, the government amended the GPDO to require planning permission for any new impermeable driveway surface over 5 square metres that does not include provision for water to drain within the property boundary. The aim was to reduce surface water runoff contributing to urban flooding.
What Counts as Impermeable?
Standard dense bitumen macadam (the default "tarmac") is impermeable. So is poured concrete, resin-bound aggregate over a sealed base, and grouted block paving. Permeable alternatives include porous asphalt, permeable block paving with open joints, gravel, and reinforced grass grid systems.
Compliance Without Planning Permission
You can avoid planning permission in three ways:
- Use a permeable surface: Porous macadam allows water to drain through the surface into the sub-base. It costs around 10 to 15% more than standard tarmac.
- Drain to a permeable area: If the drive falls towards a lawn, border, or soakaway within your property, standard tarmac is acceptable.
- Install a drainage channel: An ACO channel drain across the bottom of the drive, connected to a soakaway, intercepts runoff before it reaches the highway.
Enforcement
Enforcement is patchy. Many contractors lay impermeable drives without any drainage provision, and many local authorities do not actively pursue retrospective planning applications. However, if you sell the property and the buyer is solicitor raises it during conveyancing, you could face a retrospective planning application or, in the worst case, a requirement to reinstate.
We advise all our driveway clients on the drainage requirements before starting work. View our driveway services or see our tarmac sub-base guide.